What sort of assault rifle should I purchase?

[AzzarTheGod]

Pretty much what Pagan said.

However, the definition that the NRA uses is anything that is select-fire is an assault rifle. I believe it is not an official NRA position, but the NRA members are unofficially encouraged to shout back at anyone who calls their rifle "assault" by saying "Its not select-fire, its not an assault rifle idiot".

Select-fire = assault rifle is the general agreement among the gun community.